Question: Simplify the following expression: $y = \dfrac{8}{5q} - \dfrac{1}{10q}$
Answer: In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $5q$ and $10q$ $\lcm(5q, 10q) = 10q$ $ y = \dfrac{2}{2} \cdot \dfrac{8}{5q} - \dfrac{1}{1} \cdot \dfrac{1}{10q} $ $y = \dfrac{16}{10q} - \dfrac{1}{10q}$ $y = \dfrac{16 -1}{10q}$ $y = \dfrac{15}{10q}$ Simplify the expression by dividing the numerator and denominator by 5: $y = \dfrac{3}{2q}$